Hydraulic rotary motor

ABSTRACT

A hydraulic rotary motor, in particular to a stewing gear for elevating plant such as excavator grabs, etc., comprising a housing in which a rotor is rotatably received as well as a ring piston having an inner toothed arrangement and an outer toothed arrangement which is seated between the rotor and the housing so that displacement chambers are formed between the ring piston and an outer toothed arrangement of the rotor and/or an inner toothed arrangement of the housing, with a first motor connector being rotatably fixedly connected to the housing and a second motor connector being rotatably fixedly connected to the rotor. The hydraulic rotary motor is characterized in that the rotor is axially and radially supported at the housing via plain bearings and the second motor connector connected to the rotor is solely supported via the plain bearings at the housing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hydraulic rotary motor, in particular to a slewing gear for elevating plant such as excavator grabs, etc., comprising a housing in which a rotor is rotatably received as well as a ring piston having an inner toothed arrangement and an outer toothed arrangement which is seated between the rotor and the housing so that displacement chambers which can be filled with pressure fluid are formed between the ring piston and an outer toothed arrangement of the rotor and/or an inner toothed arrangement of the housing, with a first motor connector being rotatably fixedly connected to the housing and a second motor connector being rotatably fixedly connected to the rotor.

2. Description of the Prior Art

Such a hydraulic rotary motor is known from DE 33 42 131 A1. DE 37 29 049 C1, DE 2 365 057 or DE 196 05 879 A1 also show hydraulic rotary motors of this type in which a ring piston orbits in a gyrating manner and in this process interacts with an inner toothed arrangement at the housing and with an outer toothed arrangement at the rotor to drive the rotor in a rotary manner relative to the housing. Typically, such rotary motors are used as slewing gears for elevating plant of excavators, part-load cranes or logging cranes, wherein, when used, for example, for an excavator grab, the first motor connector fixed to the housing is connected to the excavator arm, whereas the excavator grab is installed at the second motor connector connected to the rotor. The excavator grab can be rotated in a manner known per se relative to the excavator arm via the rotary movement of the rotor relative to the housing.

With such hydraulic rotary motors of the initially named kind, the rotor is typically seated rotationally fixedly, but longitudinally displaceably on a drive shaft whose end exiting the housing forms the second motor connector for the fastening of the elevating plant. To intercept the forces and torques introduced onto the motor by the elevating plant, the motor shaft is supported on both sides of the rotor via tapered roller bearings at the housing. DE 33 42 131 or DE 37 29 049, for example, show this. Axial forces and bending torques introduced into the motor shaft should thereby largely be kept away from the rotor so that it can run smoothly and precisely in the ring-shaped housing gap in which the ring piston is received and so that the sealing of the displacement chambers does not experience any impairment by bearing forces or reaction forces onto the rotor. However, what is disadvantageous with this support of the motor shaft via tapered roller bearings is, however, the large axial construction length of the motor which hereby arises. In addition, static overdeterminations result since, in addition to the shaft support, the rotor itself must be guided precisely so that the displacement chambers do not experience any excessive leaking. In addition, the production and assembly effort is relatively high due to the corresponding components.

SUMMARY OF THE INVENTION

The present invention wants to provide a remedy here. It has the underlying object of providing an improved rotary motor of the said kind which avoids disadvantages of the prior art and further develops the latter in an advantageous manner. A compact rotary motor of simple construction and short axial design should preferably be provided which can be manufactured in a cost-favorable manner by a low production effort and use of material.

This object is solved in accordance with the invention by a hydraulic rotary motor in accordance with claim 1. Preferred aspects of the invention are the subject of the dependent claims.

In the rotary motor in accordance with the invention, a separate support of the motor shaft by the known tapered roller bearings is omitted. It is rather the case that the forces and torques introduced from the motor connector connected to the respective elevating plant are directly intercepted via the rotor itself. In accordance with the invention, the rotor is supported axially via plain bearings and radially at the housing. The second motor connector connected to the rotor for the fastening of the elevating plant is supported via the rotor and the plain bearings at the housing supporting it. By the omission of separate shaft bearings in the form of tapered roller bearings or other roller bearings and by the interception of the forces and torques via the rotor itself and corresponding plain bearings free of roller bearings, the axial construction length of the motor can be substantially shortened, on the one hand. On the other hand, the production effort and the use of material are reduced by the dispensing with of the separate roller bearings for the motor shaft, whereby cost savings can be achieved. The second motor connector connected to the rotor can in particular be rigidly connected to the rotor and be supported exclusively via the plain bearings engaging at the rotor.

In a further development of the invention, the rotor can be seated rigidly on an output shaft whose end exiting the housing forms the second motor connector for the fastening of the elevating plant. The rotor can be pressed onto the output shaft or be rigidly connected to it in another suitable manner.

To achieve a particularly compact arrangement, a motor shaft can be fully dispensed with. The rotor itself replaces the motor shaft in this connection and itself forms the motor connector for the fastening of the elevating plant which can advantageously be fastened directly to the rotor. For this purpose, the rotor can have suitable fastening means, in particular bores for the reception of bolts for the fastening of the elevating plant. The rotor expediently has a stub-shaped shoulder whose end face forms the installation surface for the elevating plant.

The rotor advantageously forms a ring in whose inner cut-out a rotary brake, preferably a multi-disk brake, can be arranged. A particularly compact arrangement is hereby achieved, on the one hand. On the other hand, the braking forces are introduced from a housing section directly into the rotor which is particularly suitable for this due to its high-strength material.

In a further development of the invention, the rotor can have a disk section which has two axially plain bearing surfaces on oppositely disposed sides with which the rotor is axially supported in opposite directions in a housing gap into which the ring piston is also inserted. The rotor can additionally have two shaft sections which project axially in the manner of a hollow shaft stub at both sides from the said disk section. In a further development of the invention, radial plain bearing surfaces are provided at the shaft sections and the rotor is supported at these on the rims of the housing gap. A stiff support of the rotor can hereby be achieved both with respect to axial forces and to radial forces and corresponding torques.

The plain bearing surfaces can generally be formed by bearing inserts which are used on the housing side and/or on the rotor side. However, in a further development of the invention, the plain bearing surfaces can be formed directly by the material or by the surface of the rotor and of the housing section adjacent thereto. If the housing is produced from gray-cast iron, good plain bearing properties can be achieved directly by the housing material.

The bearing of the rotor advantageously dispenses with the conventional distributor plates or pressing plates which are guided movably in the housing and are known, for example, from the construction in accordance with DE 33 42 131. The production effort and use of material can thereby be further reduced.

To ensure a sufficient lubrication of the plain bearing support of the rotor, an oil guiding system and/or a passage system is provided in accordance with a further aspect of the invention, in particular in the housing, which guides hydraulic oil out of the displacement chambers and/or out of the pressure supply passages of the motor to the bearing positions of the rotor and/or to the drive shaft connected thereto. Communication passages to the pressure passages for the improvement of the oil supply of the plain bearing surfaces can in particular be provided via which the displacement chambers of the motor are filled with oil and the motor is ultimately driven. The oil supply of the bearing positions via a passage system in the housing which guides hydraulic oil from the displacement chambers and/our from the pressure supply passages of the motor to the bearing positions also has considerable advantages, however, in the lubrication of rotors conventionally supported via roller bearings or of the drive shafts of such motors. In accordance with an advantageous embodiment of the invention, ring grooves can in particular be provided in the radial plain bearing surfaces of the rotor or in the corresponding radial plain bearing surfaces of the housing which are connected to a respective one of the pressure passages for the supply of the displacement chambers. The respective ring groove ensures the distribution of the oil over the total periphery. To utilize the oil pressure available from the pressure passages also for the lubrication of the axial plain bearing surfaces, transverse bores can be provided in the housing which connect the said axial plain bearing surfaces with one of the aforesaid ring grooves. Alternatively or additionally, oil bores could also lead directly from the pressure passages for the supply of the displacement chambers to the axial plain bearing surfaces.

A first set of oil supply passages is advantageously provided in the housing which are connected to a pressure passage for the supply of the displacement chambers for reverse action and a second set of oil supply passages is provided which are connected to a pressure passage for the supply of the displacement chambers for forward action.

For this purpose, two ring grooves can be formed in levels in the housing lying above one another and can each have a wave-shaped or S-shaped contour, with the wave-shaped or S-shaped contours of the two ring grooves being arranged offset with respect to one another. The ring grooves can hereby be spot drilled individually through the feed bores in the bulges without the respective other ring groove being connected as well. The wave-shaped design can advantageously be effected in casting technology, for example by insertion of correspondingly shaped tube cores.

Alternatively or additionally, preferably approximately tubular insert sleeves with infeed apertures open to a respective one ring passage can advantageously be inserted into the feed bores connected to the ring passage. In this connection, the feed bores can as such penetrate both ring grooves so that a wave-shaped or S-shaped ring passage contour can be dispensed with.

The at least one ring groove can be made open toward an inner peripheral surface of the housing, at which inner peripheral surface the rotor and/or the drive shaft connected to it is/are radially supported to ensure a lubrication at this support position.

Alternatively, the ring groove can also be made closed completely in the interior of the housing and be connected via feed bores to at least one support of the rotor and/or the drive shaft connected to it.

It has proved to be particularly advantageous for the lubrication of the axial plain bearing surfaces for transverse bores to be provided in the meshing noses of the rotor which open onto the axial plain bearing surfaces of the rotor. Oil can thereby flow from the one side of the rotor to the other in order to ensure a sufficient oil supply on both sides of the meshing noses of the rotor on which the axial plain bearing surfaces are provided.

In a further development of the invention, plate-shaped recesses can be formed in the axial plain bearing surfaces of the rotor which form pressure pockets or better distribute the oil located there. These plate-shaped recesses are in particular arranged on the side of the rotor which intercepts the tensile forces introduced from the elevating plant. The plate-shaped recesses are advantageously in communication with the transverse bores in the meshing noses of the rotor so that they are fed with oil from the other side of the rotor.

To introduce sufficient oil into the aforesaid transverse bores in the meshing noses of the rotor, distributor grooves connected to the transverse bores can be provided in the axial plain bearing surfaces, with these distributor grooves in particular being arranged on the side of the rotor disposed opposite the aforesaid plate-shaped recesses.

To ensure a circulating oil pressure and thus an exchange of oil due to circulating pressure differences in the radial plain bearing surfaces, in a further development of the invention, axial grooves for the oil distribution can be provided—in particular offset by 180—in the radial plain bearing surfaces of the housing and/or of the rotor and/or of the shaft connected thereto.

An oil guiding system or passage system is advantageously also provided for the lubrication of the ring piston for this. To transport the oil onto the axial surfaces of the ring piston, the ring piston thickness can reduce toward the edges of the outer toothed arrangement, with bevels, for example in the form of a chamfer toward the outer meshing noses, in particular being provided at the rims of the axial plain bearing surfaces of the ring piston. This facilitates the oil being able to move onto the plain bearing surfaces of the ring piston. The outwardly conical shape of the piston moreover ensures a flooding and centering of the ring piston. Furthermore, the parallelism and angle defects have a smaller effect.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail in the following with reference to preferred embodiments and to associated drawings. There are shown in the drawings:

FIG. 1 is a schematic sectional view through a rotary motor in accordance with a first preferred embodiment of the invention in which the rotor of the motor received in the housing itself forms that motor connector connectable with the elevating plant;

FIG. 2 is a schematic sectional view of a hydraulic rotary motor in accordance with an alternative embodiment of the invention in which the motor connector is formed for the fastening of a elevating plant of a motor shaft to which the rotor is rigidly connected;

FIG. 3 is a schematic plan view of the ring piston with an inner and outer toothed arrangement and the rotor cooperating therewith and the housing of the rotary motors cooperating therewith from FIGS. 1 and 2;

FIG. 4 is an axial section through the rotor of the rotary motors of FIGS. 1 and 2 which shows the transverse bores in the meshing noses for the oil supply of the plain bearing surfaces;

FIG. 5 is a plan view of the meshing noses of the rotor and the distributor grooves introduced therein and the transverse bores connected thereto;

FIG. 6 is a plan view of the side of the meshing noses of the rotor on the opposite side in comparison with FIG. 5 which shows the plate-like recesses introduced therein and the transverse bores connected thereto;

FIG. 7 is an axial section through the ring piston of the motors from FIGS. 1 and 2 which shows the ring piston thickness reducing toward the outer contour of the ring piston;

FIG. 8 1s a sectional view along the line A-A in FIG. 2 which shows lubrication grooves formed in the bearing cover of the housing;

FIG. 9 is a sectional view of the rotary motor in accordance with FIG. 2 which shows a relief bore between an axial bearing surface of the motor shaft and an oil leakage space between the ring piston and the housing;

FIG. 10 is a sectional view of the housing in the region of a pressure passage for the feeding of the displacement chambers for a rotary direction which shows a ring distributor passage in the housing and oil feed passages in communication therewith into which the sleeve-like inserts with infeed bores are inserted;

FIG. 11 is a sectional view of the housing similar to FIG. 10 along the line A-A in FIG. 13, with the ring distributor passages lying above one another each being made offset in wave shape in the embodiment in accordance with FIG. 11 so that the oil feed bores can be spot drilled directly into the respective ring distribution passage;

FIG. 12 is a sectional axial section through the housing cover which shows the position of the ring distribution passages from FIG. 11 and the connection of the lower ring distributor passage via a feed bore to the axial plain bearing surface of the rotor;

FIG. 13 is a sectional axial section of the housing similar to FIG. 12 which shows the connection of the upper ring distributor passage to the axial plain bearing surface at the rotor;

FIG. 14 is a schematic sectional view of the housing with a ring distributor passage in accordance with an alternative embodiment of the invention which is not open to the inner cut-out of the housing, whereby corresponding seals are no longer required;

FIG. 15 is a schematic sectional view of a rotary motor similar to FIG. 2, with here the oil supply of the plain bearing surfaces for the rotor or the shaft being fed from a pressure passage for the pressure supply of the elevating plant connectable to the rotary motor; and

FIG. 16 is a schematic sectional view of a rotary motor similar to FIG. 15, with here the rotor side loaded on tensile forces introduced from the elevating plant being fed with pressure oil from the pressure supply passage which is provided for the supply of the elevating plant attachable to the rotary motor.

DETAILED DESCRIPTION OF THE INVENTION

The rotary motor 1 shown in FIG. 1 comprises a substantially cup-shaped housing 2 which consists in the drawn embodiment substantially of three parts, namely the motor head 3, the rotor housing ring 4 and the bearing cover 5. As FIG. 1 shows, the bearing cover 5 is set on the rotor housing ring 4 and is screwed via screw connections 6 to the radially projecting flange 7 of the motor head 3 so that an annular rotor gap 8 is formed between the bearing cover 5 and the motor head 3. The ring piston 9 is received in the said rotor gap 8 as is—radially inside this ring piston 9—the substantially likewise disk-shaped rotor 10. In more precise terms, a disk section 11 of a rotor/shaft unit is seated with an exact fit between the bearing cover 5 and the motor head 3. Shaft sections 12 and 13 are shaped in a projecting manner at both sides of the disk section 11 and their outer periphery runs with an exact fit on inner peripheral surfaces of the bearing cover 5 or of the motor head 3.

As FIG. 3 shows, the ring piston 9 is provided with an inner toothed arrangement 14 and with an outer toothed arrangement 15 and interacts therewith, on the one hand, with an outer toothed arrangement 16 of the rotor 10 and, on the other hand, with an inner toothed arrangement 17 of the rotor housing ring 4 in a manner known per se. The ring piston 9 can be driven in an orbiting gyratory manner by pressure fluid charging of the displacement chambers 18 formed between the ring piston 9 and the rotor 10 or the rotor housing ring 4, whereby said ring piston drives the rotor 10 via the toothed arrangements relative to the rotor housing ring 4 and thus to the housing 2 as is described in detail in DE 33 42 131 A1 to which reference is made in this respect.

As FIG. 1 shows, the rotary motor fully dispenses in this embodiment of the invention with a separate motor shaft which is replaced by the rotor 10. The end face 19 of the shaft section 13 of the rotor 10 exiting the housing 2 forms a motor connector 20 to which an elevating plant 21 such as an excavator grab can be attached. For this purpose, bolts 22 are provided in the rotor 10. The other motor connector 23 is formed in a manner known per se by the motor head 3 of the housing 2 with which the rotary motor 1 can be attached, for example, to the arm of an excavator.

As FIG. 1 furthermore shows, the rotor 10 is made as a ring. A rotary brake 25 in the form of a multi-disk brake is arranged in the hollow inner space 24 of the rotor 10 and does not extend axially beyond the rotor and ensures a particularly compact design of the motor. The inner peripheral surface of the rotor 10 supports, for example via a spline profile, a set of the multiple disks of the rotary brake 25 whose other set of multiple disks is rotationally fixedly supported at a sleeve-like catch piece 26 which is itself likewise fastened rotationally fixedly to the housing 2. The multiple disks of the rotary brake 25 can be pressed onto one another via a brake piston 27 in the intermediate space between the said catch piece 26 and the rotor 10 and the braking effect can hereby be effected.

As FIG. 1 shows, the rotary motor 1 dispenses fully with roller bearings. The forces and torques introduced by the elevating plant 21 are intercepted solely via the rotor 10 itself and the plain bearings supporting it at the housing 2. The rotor 10 comprises for this purpose, on the one hand, axial plain bearing surfaces 28 and 29 which are formed by the oppositely disposed flat sides of the disk section 11 of the rotor 10. On the other hand, the rotor 10 comprises radial plain bearing surfaces 30 and 31 which are formed by the outer peripheral surfaces of the shaft sections 12 and 13 of the rotor 10. It is understood that corresponding plain bearing surfaces are provided at the housing 2 which cooperate with the said axial plain bearing surfaces 28 and 29 and with radial plain bearing surfaces 30 and 31.

Roller bearings are also dispensed with in the embodiment of the rotary motor 1 shown in FIG. 2. The forces and torques introduced from the elevating plant 21 are also intercepted here solely via plain bearings. The rotor 10 is in particular also axially supported at the housing 2 here via axial plain bearing surfaces 28 and 29 on the flat sides of its disk section 11. In contrast to the embodiment of FIG. 1, the ring-shaped rotor 10 is, however, pressed onto a drive shaft 32 in this embodiment. The rotor 10 is rigidly connected to the drive shaft 32 so that both axial forces and bending torques and radial forces from the drive shaft 32 are introduced into the rotor 10 or are, vice versa, intercepted by the latter. The radial plain bearing surfaces 30 and 31 are provided in the embodiment of FIG. 2 at the shaft sections 12 and 13 of the drive shaft 32 which axially adjoin the rotor 10. Since the rotor 10 is seated on the drive shaft 32 in the embodiment of FIG. 2, it is not the rotor 10 itself which forms the motor connector for the fastening of the elevating plant. The motor connector 20 is formed by the end face 19 of the end of the drive shaft 32 exiting the housing 2 (cf. FIG. 2).

For the oil supply of the axial and radial plain bearing surfaces 28, 29, 30 and 31, various oil passages are formed in the rotor 10 and in the housing 2 through which the oil is guided in a sufficient amount to the said plain bearing surfaces.

On the one hand, such passages are provided in the rotor 10 in order to have sufficient oil on both axial plain bearing surfaces 28 and 29. As FIG. 4 shows, transverse bores 34 are provided in the meshing noses 33 of the rotor 10 which connect the axial plain bearing surface 28 on the upper side of the rotor 10 to the axial plain bearing surface 29 on the lower side of the rotor 10. Oil can thereby be guided onto the lower bearing surface from the upper side of the rotor 10. In addition, a pressure compensation or a higher pressure can be generated on the lower axial plain bearing surface 29, whereby the operating loads are compensated to a specific degree which are introduced by tensile forces via the elevating plant 21.

As FIG. 5 shows, distributor grooves 35 are provided in the axial plain bearing surface 28 on the upper side of the rotor 10 which extend approximately tangentially to the peripheral direction and are connected to the aforesaid transverse bores 34. This improves a continuous oil flow to the lower support position and a corresponding pressure build-up. In a further development of the invention, the distributor grooves 35 are made very narrow so that the axial pressure remains low. The width of the distributor grooves 35 can amount to less than 1 mm.

On the side opposite the distributor grooves 35, the transverse bores 34 passing through the meshing noses 33 open into plate-shaped recesses 36, as FIG. 6 shows. These large-area pressure pockets improve the lubrication of the lower axial plain bearing surface 29 and can support or ensure a sliding of the rotor 10 with respect to the bearing cover 5 even at higher operating loads. The axial plain bearings can hereby be relieved hydraulically against the main direction of force, i.e. the tensile forces introduced via the elevating plant 21.

It is possible by the oil supply of the axial plain bearing surfaces 28 and 29 from the inside via the said transverse bores 34 to form the outer contour of the rotor 10 and the inner contour of the ring piston 9 without chamfers or other bevels. Such bevels or slight chamfers toward the pressure chamber would likewise per se ensure a pressure supply of the plain bearing surfaces 28 and 29 and ensure a certain sliding of the rotor 10 or of the ring piston 9 in the oil bath. On the other hand, this results in a leak in the chamber region which is avoided in the sharp-edge design. Nevertheless, the inner supply of the axial plain bearing surfaces 28 and 29 via the transverse bores 34 ensures that no interruption of the oil film occurs.

The plain bearing surfaces 28 and 29 are advantageously fed via feed bores from pressure passages which are provided either for the pressure supply of the displacement chambers 18 or for the pressure supply of an attached elevating plant in the housing 2. For this purpose, ring distributor passages 37 and 38 are advantageously introduced in the motor head 3, as FIGS. 10 to 14 show, which are arranged at different vertical levels and are in each case connected to one of the oil supply passages for in each case one direction of rotation. As FIGS. 12 and 13 show, feed bores 39 and 40 lead from the said ring distributor passages 37 and 38 to the axial plain bearing surface 28. The oil led there can then be guided in the previously described manner via the transverse bores 34 formed in the meshing noses 33 to the oppositely disposed axial plain bearing surface 29.

As FIG. 10 shows, the ring distributor passages 37 to 38 on the inner peripheral surface of the housing 2 which supports the radial plain bearing surface 30 of the rotor 10 are made open toward the inner side so that they can be introduced by mechanical working and ensure a lubrication of the radial plain bearing surfaces there. Every second feed bore 39 to 40 can be connected by spot bores to the respective ring distributor passage 37 or 38 respectively. In this process, the feed bores 39 and 40 can be drilled through or into both ring distributor passages 37 and 40 and then sleeve-shaped inserts 50 can be inserted into the feed bores which have an infeed bore at a respectively matching height and thus connect the respective feed passage 39 and 40 to the desired ring distributor passage 37 or 38, cf. FIG. 10.

FIG. 11 shows an alternative embodiment of the ring distributor passages 37 to 38. Here, each ring distributor passage 37 or 38 is made in a technical casting manner such that the feed bore 39 to 40 can be directly spot drilled offset to the respective other passage. FIG. 12 and FIG. 13 show this in section. As FIG. 11 shows, the two passages each have a shaft contour offset to one another so that a respective bulge 51 of the one ring distributor passage 37 can be spot drilled without hitting the other ring distributor passage 38.

Alternatively to the inwardly open design, the ring distributor passages 37 and 38 can also be made closed completely in the interior of the housing 2, as FIG. 14 shows, e.g. by a suitable casting technology. This has the advantage that no seals have to be provided on the inner peripheral surface of the housing 2. The ring distributor passages 37 and 38 are here also advantageously made in wave shape and directly spot drilled so that the feed bores 39 and 40 communicate with the respective ring distributor passage 37 or 38.

Alternatively or additionally, a lubrication of the plain bearing surfaces can also take place from the pressure passage 41 in the housing 2 which is provided for the pressure supply of the elevating plant 21 attached to the rotary motor 1. As FIG. 15 shows, a pressure lead 42 can, for example, charge a ring space between the housing and the drive shaft 32 which thereby acts so-to-say as a piston and effects a pressure relief. The pressure lead 42 is preferably connected to the closing force pressure lead 41 so that when closing force is applied, the pressure relief is ensured.

As FIG. 9 shows, an oil supply of the plain bearing surfaces can also take place from the oil leakage space 43 which is formed between the ring piston 9 and the rotor housing ring 4. The oil leakage space 43 is advantageously charged with a relatively low pressure, which can actually serve the foaming of the oil and can be effected via control valves, but advantageously also ensures the lubrication.

The axial grooves 44 which accept the shaft sections 12 and 13 of the rotor 10 or of the drive shaft 32 are advantageously arranged offset to one another by 180—in the inner peripheral surfaces of the bearing cover 5 and/or of the motor head 3. It can thereby be achieved that an oil exchange takes place in the radial plain bearing surfaces 30 and 31 by the peripheral oil pressure.

In order also to achieve a lubrication of the ring piston 9, provision can be made in an advantageous further development of the invention, as FIG. 7 shows, that the thickness of the ring piston 9 reduces toward its outer contour. A corresponding flattening or beveling 45 ensures that oil from the oil leakage space 43 can spread over the upper side or lower side of the ring piston 9. The ring piston 9 so-to-say is flooded and is sufficiently lubricated at its upper side and lower side. In addition the parallelism and angle errors have a lower effect. 

1. A hydraulic rotary motor, in particular slewing gear for an elevating plant such as excavator grabs, etc., comprising a housing (2) in which a rotor (10) is rotatably received as well as a ring piston (9) having an inner toothed arrangement (14) and an outer toothed arrangement (15) which is seated between the rotor (10) and the housing (2) so that displacement chambers (18) are formed between the ring piston (9) and an outer toothed arrangement (16) of the rotor (10) and/or an inner toothed arrangement (17) of the housing (2), with a first motor connector (23) being rotatably fixedly connected to the housing (2) and a second motor connector (20) being rotatably fixedly connected to the rotor (10), characterized in that the rotor (10) is supported axially and radially at the housing (2) via plain bearings (28, 29, 30, 31) and the second motor connector (20) connected to the rotor (10) is solely supported via the plain bearings (28, 29, 30, 31) at the housing (2).
 2. A rotary motor in accordance with claim 1, wherein the rotor (10) is rigidly seated on a drive shaft (32) whose end exiting the housing (2) forms the second motor connector (20).
 3. A rotary motor in accordance with claim 1, wherein the rotor (10) itself forms the second motor connector (20).
 4. A rotary motor in accordance with claim 1, wherein the rotor (10) forms a ring.
 5. A rotary motor in accordance with claim 1, wherein a rotary brake (24), in particular a multi-disk brake, is arranged in an inner cut-out (24) of the rotor (10).
 6. A rotary motor in accordance claim 1, wherein the rotor (10) has a disk section (11) which has two axial plain bearing surfaces (28, 29) on oppositely disposed sides with which the rotor (10) is supported in a housing gap (8) in which the ring piston (9) is also arranged and wherein shaft sections (12, 13) of the rotor (10) projecting axially at both sides at the disk section (11) or of a drive shaft (32) rigidly connected to it have radial plain bearing surfaces (30, 31) with which the rotor (10) is supported at the rims of the housing gap (8).
 7. A rotary motor in accordance with claim 1 wherein oil supply passages (37, 38, 39, 40) are provided in the housing (2) for the bearing positions of the rotor (10) which can be fed from a pressure passage for the supply of the displacement chambers (18).
 8. A rotary motor in accordance with claim 7, wherein a first oil supply passage or a set of oil supply passages (38, 40) are provided in the housing (2) which can be connected to a pressure passage for the supply of the displacement chambers (18) for reverse action and a second oil supply passage or set of oil supply passages (37, 39) are provided which can be connected to a pressure passage for the supply of the displacement chambers (18) for forward action.
 9. A rotary motor in accordance with claim 1, wherein at least one ring groove (37, 38) is provided in the housing (2) and is connected to one of the pressure passages for the supply of the displacement chambers (18).
 10. A rotary motor in accordance with claim 9, wherein the at least one ring groove (37, 38) is connected via feed bores (39, 40) to at least one axial plain bearing surface (28).
 11. A rotary motor in accordance claim 1, wherein the at least one ring groove (37, 38) is made open toward an inner peripheral surface of the housing (2) at which the rotor (10) and/or the drive shaft (32) connected thereto is/are radially supported.
 12. A rotary motor in accordance with claim 9, wherein the at least one ring groove (37, 38) is made closed completely in the interior of the housing (2) and is connected via feed bores to at least one bearing support of the rotor (10) and/or of the drive shaft (32) connected thereto.
 13. A rotary motor in accordance with claim 1, wherein two ring grooves (37, 38) are arranged in planes lying above one another and each have a wave-shaped or S-shaped contour, with the wave-shaped or S-shaped contours of the two ring grooves (37, 38) being arranged offset to one another.
 14. A rotary motor in accordance with claim 1, wherein preferably approximately tubular inserts (50) with infeed openings open to a respective ring passage (37, 38) being inserted into the feed bores.
 15. A rotary motor in accordance with claim 1, wherein transverse bores (34) which open onto the axial bearing surfaces (28, 29) of the rotor (10) are provided in the meshing noses (33) of the rotor (10).
 16. A rotary motor in accordance claim 1, wherein plate-shaped pressure pockets are formed in the axial plain bearing surfaces (28, 29) of the rotor (10).
 17. A rotary motor in accordance with claim 1, wherein distributor grooves (35) connected to the transverse bores (34) are provided in the axial plain bearing surfaces (28, 29).
 18. A rotary motor in accordance with claim 1, wherein the ring piston (9) has a thickness reducing toward the rims of its outer toothed arrangement (15).
 19. A rotary motor in accordance with claim 18, wherein bevels (45) toward the displacement chambers (18) are provided at the rims of the ring piston (9).
 20. A rotary motor in accordance with claim 1, wherein axial grooves, preferably displaced by 180—with respect to one another, are provided in the radial plain bearing surfaces of the housing (2) and/or of the rotor (10) and/or of the shaft (32) connected thereto.
 21. A rotary motor in accordance with claim 1, wherein at least one compensation bore is provided between a radial plain bearing surface and an oil leakage space (43) between the ring piston (9) and the housing (2).
 22. A rotary motor in accordance with claim 10, wherein the at least one ring groove (37, 38) is made closed completely in the interior of the housing (2) and is connected via feed bores to at least one bearing support of the rotor (10) and/or of the drive shaft (32) connected thereto. 